package thinkingInJava.concurrency;
//: concurrency/InterruptingIdiom.java
// General idiom for interrupting a task.
// {Args: 1100}
import java.util.concurrent.*;
import static thinkingInJava.YTool.YPrint.*;

class NeedsCleanup {
	private final int id;
	public NeedsCleanup(int ident) {
		id = ident;
		print("NeedsCleanup " + id);
	}
	public void cleanup() {
		print("Cleaning up " + id);
	}
}

class Blocked3 implements Runnable {
	private volatile double d = 0.0;
	public void run() {
		try {
			while(!Thread.interrupted()) {
				// point1
				NeedsCleanup n1 = new NeedsCleanup(1);
				// Start try-finally immediately after definition
				// of n1, to guarantee proper cleanup of n1:
				try {
					print("Sleeping");
					TimeUnit.SECONDS.sleep(1);
					// point2
					NeedsCleanup n2 = new NeedsCleanup(2);
					// Guarantee proper cleanup of n2:
					try {
						print("Calculating");
						// A time-consuming, non-blocking operation:
						for(int i = 1; i < 2500000; i++)
							d = d + (Math.PI + Math.E) / d;
						print("Finished time-consuming operation");
					} finally {
						n2.cleanup();
					}
				} finally {
					n1.cleanup();
				}
			}
			print("Exiting via while() test");
		} catch(InterruptedException e) {
			print("Exiting via InterruptedException");
		}
	}
}

public class InterruptingIdiom {
	public static void main(String[] args) throws Exception {
		if(args.length != 1) {
			print("usage: java InterruptingIdiom delay-in-mS");
			System.exit(1);
		}
		Thread t = new Thread(new Blocked3());
		t.start();
		TimeUnit.MILLISECONDS.sleep(new Integer(args[0]));
		t.interrupt();
	}
} /* Output: (Sample)
NeedsCleanup 1
Sleeping
NeedsCleanup 2
Calculating
Finished time-consuming operation
Cleaning up 2
Cleaning up 1
NeedsCleanup 1
Sleeping
Cleaning up 1
Exiting via InterruptedException
 *///:~
